Excel Data Cleaning Workflow

Excel Data Cleaning Workflow

From Raw Data to Business Insights

Choosing the right cleaning approach: Excel Worksheets, Power Query GUI, and Power Query M Language. Tap any step to see what it does.

1SOURCE
RAW DATA
Ingested from multiple sources
Native .xlsx/.xls files. Load specific sheets, named ranges or tables directly, keeping types and structure.
Plain-text delimited exports. Universal and lightweight, but carry no data types or formatting, so typing is your first job.
SQL sources such as SQL Server or Access. Query live or import into the model, ideal for large, governed datasets.
Tables scraped from web pages or JSON/REST API responses, pulled fresh every time the query refreshes.
2ASSESS

Data Quality Assessment

Profile every issue before choosing a cleaning path

Empty cells or nulls that break formulas, skew averages and hide gaps in your data.
Repeated rows that inflate counts, totals and metrics if they are not removed.
Numbers or dates stored as text, which blocks math, sorting and correct aggregation.
Mixed case, stray spaces, and varied units or date formats that stop values from matching.
Structural gaps that fragment ranges and tables and confuse downstream tools.
Extreme values and error codes like #REF!, #N/A and #DIV/0! that distort analysis.
Choose a path
3CLEAN
11 steps

Direct Excel
Worksheet Cleaning

  • Data ▸ Sort & Filter · Ctrl+Shift+L Reorder rows or hide the ones you don't need so problem records are easy to spot.
  • Ctrl+H (supports * and ? wildcards) Swap text across the whole sheet in one pass, ideal for fixing typos or codes in bulk.
  • =TRIM(text) Removes leading, trailing and double spaces, keeping single spaces between words.
  • =CLEAN(text) Strips non-printable characters (line breaks, control codes) pasted from other systems.
  • =SUBSTITUTE(text, old_text, new_text, [instance_num]) Replaces specific text inside a cell. Case-sensitive, and you can target the nth match.
  • =LEFT() =RIGHT() =MID() =LEN() =PROPER() Slice, measure and re-case text, pull out codes, fix capitalisation, standardise strings.
  • Data ▸ Flash Fill · Ctrl+E Type one or two examples and Excel fills the rest by matching the pattern automatically.
  • Data ▸ Remove Duplicates Deletes duplicate rows based on the columns you tick, keeping the first of each.
  • Data ▸ Data Validation Limits what can be typed (a list, a number range, a date) to stop bad data at entry.
  • Home ▸ Conditional Formatting Colours cells by rule so blanks, duplicates and outliers stand out at a glance.
  • =IFERROR(value, value_if_error) Runs a formula and returns a clean fallback (like "" or 0) instead of #N/A or #DIV/0!.

BEST FOR

  • Small datasets
  • Quick one-time cleaning
  • Learning Excel fundamentals
AutomationLow
Skill LevelBeginner
14 steps

Power Query
GUI

  • Data ▸ Get Data ▸ From File / Database / Web Connect to a source as a refreshable query, the raw data stays untouched.
  • Home ▸ Use First Row as Headers Turns the first row of data into proper column names.
  • Home ▸ Data Type (or the column-header type icon) Sets each column to text, number, date etc. so operations behave correctly.
  • Home ▸ Split Column ▸ By Delimiter Breaks one column into several by a delimiter, character count or case change.
  • Add Column ▸ Merge Columns Joins several columns into one using a separator you choose.
  • Transform ▸ Replace Values Finds and replaces values in a column as a recorded, repeatable step.
  • Home ▸ Remove Rows ▸ Remove Duplicates Keeps only distinct rows based on the selected columns.
  • Transform ▸ Fill ▸ Down / Up Copies a value into adjacent blank cells, handy after unmerging grouped data.
  • Add Column ▸ Conditional Column Builds a new column with if / then / else logic through a no-code dialog.
  • Home ▸ Group By (or Transform ▸ Group By) Aggregates rows, sum, count, average, grouped by one or more key columns.
  • Home ▸ Merge Queries Joins two queries on matching columns, like a SQL join or a smarter VLOOKUP.
  • Home ▸ Append Queries Stacks the rows of multiple tables into one combined query.
  • Transform ▸ Pivot Column Turns the unique values in a column into new columns.
  • Transform ▸ Unpivot Columns Turns columns into tidy attribute/value rows, the key to clean, model-ready data.

BEST FOR

  • Medium and large datasets
  • Repeatable ETL
  • Business reporting
AutomationHigh
Skill LevelIntermediate
12 steps

Power Query
M Language

  • Table.SelectRows(table, each [Col] > 0) Filters rows to only those where your condition is true.
  • Table.RemoveColumns(table, {"Col1", "Col2"}) Drops the named columns from the table.
  • Table.TransformColumns(table, {{"Col", Text.Upper}}) Applies a function to every value in the chosen column(s).
  • Table.ReplaceValue(table, "old", "new", Replacer.ReplaceText, {"Col"}) Replaces matching values within the specified columns.
  • Table.Distinct(table, optional {"Col"}) Removes duplicate rows, optionally keyed on specific columns.
  • Table.FillDown(table, {"Col"}) Fills empty (null) cells with the value above them.
  • Table.Unpivot(table, {"Q1", "Q2"}, "Attribute", "Value") Converts wide columns into attribute/value rows in code.
  • Table.Pivot(table, values, "Attribute", "Value") Converts row values into columns in code.
  • Table.Combine({Table1, Table2}) Appends multiple tables into a single table.
  • fnClean = (x as text) => Text.Trim(Text.Upper(x)) Wrap reusable logic in a named function and call it anywhere in your queries.
  • Home ▸ Manage Parameters ▸ New (used as #"Param") Named inputs that make a query dynamic, swap a folder path or date without editing steps.
  • let Source = … in Result (saved & referenced by name) Save queries and functions once, then reference them across your whole model.

BEST FOR

  • Enterprise ETL
  • Advanced automation
  • Custom transformations
AutomationVery High
Skill LevelAdvanced
4VALIDATE
Cleaned & Validated Data
Consistent, deduplicated, correctly typed and analysis-ready
5ANALYZE

Analysis & Visualization

Turn clean data into models, charts and dashboards

Summarise and cross-tabulate large tables interactively without a single formula.
Visualise trends, comparisons and distributions with native Excel charts.
An in-memory data model with relationships and DAX measures for serious analysis.
Publish interactive, shareable dashboards and reports for the whole organisation.
6DECIDE
Business Intelligence & Decision Making
The payoff: clean data drives confident action
Formatted, refreshable outputs that keep stakeholders aligned on the same numbers.
Track key metrics against targets at a glance, so problems surface early.
Confident, data-backed choices by leadership instead of gut feel.
Spot the opportunities and trends that drive measurable, repeatable growth.
Align long-term direction with evidence rather than assumption.
★LEARNING JOURNEY
ROADMAPyour path from spreadsheets to automated intelligence
1Raw Data
2Excel Cleaning
3Power Query GUI
4Power Query M
5Automated ETL
6Analytics
7Dashboards
8Business Decisions
Excel Data Cleaning Workflow · Excel Worksheets · Power Query GUI · Power Query M
Excel Data Cleaning Workflow
Created by Ada Innocent Ada, NCMD
for Data Tribe · by Awake to Power Communications
© Awake to Power Communications 2026
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